Means and techniques for making electrical connections



Nov. 3, 1964 L. M. GRISWOLD MEANS AND TECHNIQUES FOR MAKING ELECTRICALCONNECTIONS Filed April 2l, 1964 Mlllumulummw M6. Z. m20

INVENTOR. 5E/1J. 65?/5 WO two ribbon-type cables.

United gStates Patent Ollice 3de-@99 MEANS AND TECHNlQUES FR MAKINGELECTRECAL CQNNECHNS Lee M. -riswold, Pasadena, Calif., assigner toDigital Sensors Inc., Los Angeles, Calif., a corporation of CaliforniaFiled Apr. 21, i964, Ser. No. 361,490 9 Claims. (Cl. 219-86) The presentinvention relates generally to a method and apparatus for making anelectrical connection to a conductor embedded in insulating material andis particularly useful for making electrical connections to a flexibleribbon-type cable in which the body of the ribbon is a plasticinsulating material and parallel-spaced, thin ribbon-type conductors arespaced and embedded in the plastic ribbon. l

The present 'application is a`continuationinpart of -rny copendin'gapplication Serial No. 176,729, tiled March l, 1962, now abandoned.

Briefly, the arrangement as described herein involves the use of a pairof heated electrodes between which the parts to be electricallyconnected are disposed. One of such parts is a ribbon-type cable asdescribed above and the other part may, for example, be a similarribbontype cable or an insulated or an uninsulated wire or terminal pin.The parts .to be electrically connected are squeezed together by theheated electrodes, forcing themselves through the insulation 'by heatsoftening and owing or crowding of the insulation until those metalparts that are ultimately .to be electrically connected are in physicalContact, after which a welding current is passed between the electrodesand parts to spot-weld or resistance-weld such parts together in apermanent electrical connection. The welding current may be initiatedeither in accordance with a signal developed when the parts are inmetallic Contact or when the pressure betweenl the electrodes exceeds apredetermined amount.

It is therefore an object of the present invention to provide new meansand techniques for accomplishing the above-described operations andresults.

A specific object of the present invention is `to provide improved meansand techniques for making electrical connections to a flexibleribbon-type cable.

Another specific object of the present invention is to provide improvedmeans and techniques for selectively connecting diferent `conductors ofdifferent ribbon-type cables together in a permanent electricalconnection without appreciably increasing the overall thickness of theAnother specific object of the present invention is to provide improvedmeans and techniques for making terminal connections to conductors of a.flexible ribbon-type cable.

The features ofthe present invention whichv are believed to be novel areset forth with particularity in the appended claims. This inventionitself, both as to its organization and manner of operation, togetherwith further objects and advantages thereof, may be best understood byreference to the following description taken connection with theaccompanying drawings in which:

FIG. 1 is a top plan view of two ribbon-type cables which areelectrically interconnected in accordance with features of the presentinvention.

FIG. 2 illustrates the apparatus for producing the connectionillustrated in FIG. l.

FIG. 3 is an enlarged view of a portion of the two ribbomtype cablesillustrated in FIG. l.

FIG. 4 .is a view similar to FIG. 3 and exemplifies other types ofconnections between the two ribbon-type cables.

tresses Patented Nov. 3, 1964 FIG. 5 is a sectional view generally asindicated by the line 5J-5 in FIG. 4 prior, however, to commencement ofthe operation performed by the apparatus shown in FIG. 2.

FlG'. 6 is a view like FlG. 5 and serves to illustrate the completion ofone electrical connection and also the position of the electrodes at thetime the welding current is passed therethrough for bonding adjacentconductors in adjacent cables.

FIG. 7 is a perspective view illustrating one step in the process ofconnecting a connector pin or tap or wire or solder pin to a conductorof a ribbon-type cable.

FiG. 8 is a perspective View for purposes of illustrating another methodand the resulting terminal construction.

The ribbon-type cables referred to herein are commercially availableand, as illustrated in FlG. l, comprise an assembly of spaced thinribbon-type copper conductors l@ embedded in a thin ribbon-shapedplastic ll which may be of polyethylene, a polyester or Mylar. Suchinsulating material may either be a thermoplastic resin or athermosetting resin. A like ribbon-type cable, to which electricalconnections are made, is illustrated as having conductors 2d andinsulating material 2l, and the latter ribbon-type cable, as sho-wn inFIG. l, has four connector pins or solder pins connected thereto usingthe method illustrated in FIG. 7.

FIG. l illustrates two electrical connections between the two cables,such connections being illustrated at 39 and Si, and such connectionsare made as now described in connection with FIG. 2.

In FlG. 2, there is provided heated spot-welding type electrodes ed and41 between which the ribbon-type cables are disposed. The electrodes litand il are in the form of pointed rods and are each bolted inheat-conductive relationship to a relatively heavy massive metal bar l2and 43, respectively, such bars being in heatconductive relationshipwith corresponding electric heaters stand 45 supplied with heatingcurrent through the heater wires illustrated. The lower electrode il ispreferably maintained stationary and `serves in the nature of an anvil,while the upper electrode ttl is movable for compressing the adjacenttape sections together in the manner illustrated in FIGS. 5 'and 6. FIG.5 illustrates the initial position of the electrodes dll and 4l, andFIG. 6 illustrates their nal position wherein the electrodes 40 and filare in electrical Contact with corresponding conductors in correspondingcables.

It will be seen that FIGS. 4, 5 and 6 have reference to a vditferentarrangement of connections between the conductors of the four-conductorcable 2li, 2l and the sevenconductor cable lil, Il for purposes ofdemonstrating the versatility of the invention and in such case thereare four electrical connections 32, 33, 34 and 35. Two of the conductorslll, as illustrated, are interrupted as, for example, by piercing orshearing portions out of the tape lll, 11. The interrupted ends of oneof the conductors Ill, as illustrated in FIG. 4, are connected at 32 and33 to different conductors 2G; and likewise, the interrupted ends of adifferent conductor lil are connected at 34 and 35 to other conductorsZtl.

During the application of pressure between the electrodes 40 and di,heat is transferred from such electrodes lil and 4l to the insulationll. and 21 to soften and crowd such insulation out of the path of theadvancing electrodes 4b and 4l and also to soften and crowd theinsulation between conductors It? and 2t) until ultimately there is ametal-to-metal contact between electrode 4G and conductor lt), and alsoa metal-to-metal contact between electrode lll and conductor 20, andalso a metalto-metal contact between the conductors 1t) and 2li. Whenthis condition is achieved, a welding current is caused to flow throughthis series electrical circuit decasacca .es scribed from source i)which has one of its terminals connected to the electrode lll and theother one of its terminals connected to the electrode 4l. Such weldingcurrent is caused to flow automatically when the abovementionedcondition is achieved, using eitheroue of two techniques now described.As illustrated in FIG. 2, there is provided a pressure-sensitive switch5l having its actuating element in the path of movement of the movableelectrode structure 4d, d2, ld so as to be actuated thereby when theforce or pressure applied to such moving electrode structure exceeds apredetermined amount, in which case the switch 5l is closed to fullyenergize the source 5d and to produce the above-described ilow ofwelding current between electrodes lil and lil. For purposes ofillustration, such switch 5l is illustrated as being actuateble by theextension 425A of plate 42. A source of welding current so controlledmay be, for example, of the type made under the name Weldmatic by UnitekCorporation of Monrovia, California.

An alternative arrangement for initiating the flow of welding currentinvolves an electric sensing circuit which is closed when the conditionillustrated in FIG. 6 is established, whereupon such sensing circuit isoperative to produce full energization of the welding current source Si?and resulting flow of welding current between electrodes dll and 4l.

The technique is also applicable to welding connector pins or solderingpins E@ to the ends of the four-conductor cable 2li, 2l as illustratedin FlG. 7. ln this case, the connector pin 3@ is a bare wire and themovable electrode llt) is then provided with a conforming arcuategrooved portion drlA at its end for snugly engaging the wire .':lllAwhen and as it is being heated and being pressed through the insulationEl and into metallic engagement with the underlying conductor Ztl.Simultaneously, the lower heated electrode (il also softens the adjacentinsulation and crowds itself into metallic contact with the underside ofthe conductor Ztl. The flow of welding current is then initiated asdescribed above.

Referring to FIG. 8, it illustrates another method of achievingelectrical Contact and mechanical connection of a connector pin orsoldering pin l@ to each of the ends of a multiconductor cable 120,llZl. In this case, the connector pin lSli is a bare wire which isinitially placed in physical contact with a cable conductor l2@ byphysically inserting an end of the pin in a sandwiched condition betweensuch conductor and that portion of the insulating material overlying thesame. To facilitate such insertion, one end of the pin may be pointedfor easy insertion and/or a narrow small cutting tool such as, forexample, an end portion of a razor blade may be used to separate theplastic insulating material from the conductor. In any case, theinsertion of the pin results in the overlying insulating plasticmaterial being crowded away from the conductor and forming a conformingpocket for the pin which is then self-maintained in such pocket by thestressed or stretched insulating material. While the end connection thusformed by the protruding pin may be used, preferably a better mechanicaland electrical connection between the pin and cable conductor isprovided using techniques described above and the electrodes 40 and 4lin FIG. 7 which then function to penetrate the insulating material fromeach side as a result of heat and pressure supplied to each electrode;and when the corresponding electrode 49, dl is in contact with the pini339 and conductor 12d, the pin and conductor are welded together.

The pins l2@ prior to insertion may be tnned with solder and may in somecases, after being positioned as shown in FIG. 8, be soldered to theprotruding end portion of the cable conductor.

The plastic insulating material may he, for example, Tellen in thevarious embodiments.

The connecting end pins in FIGS. 7 and 8 may be of various gauge, forexample, of 2l), 22 or 24 gauge and be silver or gold plated nickelpins. The fusing of the various elements may be accomplished by weldingor brazing or by soldering in one form of the invention described inFIG. 8 in some cases.

Usually, in making the end connections o-f FIGS. 7 and 8, the endconnector is fused to the cable conductor at two spaced locations withtwo successive fusing operations using a single pair of electrodes or ina single operation using two pairs of electrodes.

While the particular embodiments of the present invention have beenshown and described, it will be obvi- -ous to those skilled in the artthat changes and modifications may be made without departing from thisinvention in its broader aspects and, therefore, the aim in the appendedclaims is to cover all such changes and modiiications as fall within thetrue spirit and scope of this invention.

l claim:

l. Apparatus for making electrical connections .to ilexible ribbon-tapecables wherein conductors irl the form or ribbons are embedded in aplastic material, a pair of pointed electrodes capable of applyingpressure in a limited are-a to opposite sides of said tape cable,heating means mounted on each of said electrodes for soften-ing theinsulation of said tape cable when and as pressure is being applied toand between said electrodes.

2. ln a method of making electrical connections beltween conductors oftwo iiexible ribbon-type cables each of which comprise ribbon-typeconductors embedded in a plastic insulating material, the stepscomprising sandwiching said cables between a pair of heated electrodes,applying pressure between said electrodes to soften and crowd theplastic insulation out of that region between electrodes and adjacentconductors and between adjacent conductors, and applying a weldingcurrent through said elements after such heating and application ofpressure results in a metal-.to-metal contact between adjacentconductors and between adjacent electrodes.

3. ln the method for making electrical connections between conductors ofdilferent ribbon-type cables wherein such conductors rare embedded in aplastic insulating material, the steps comprising superimposing one ofsuch cables on a second cable with the desired conductors to beconnected in superimposed relationship, applying heat and pressuresimultaneously between the insulating material which overlies suchdesired conductors to soften and crowd the insulating material away fromsuch desired conductors, and thereafter passing a welding currentthrough the superimposed conductors.

4. Apparatus for making electrical connections to an insulating bodyhaving conducto-rs in the form of ribbons in said body, a pair ofpointed electrodes capable of [applying pressure in a limited area toopposite sides of said body, heating means on each of said electrodesfor softening the insulation on said body when and as pressure is beingapplied to and between said electrodes.

5. In vthe method of making electrical connections between conductors oftwo insulating bodies each of which comprise ribbon-type conductors on aplastic insulating material, .the steps comprising sandwiching saidbodies between a pair of heated electrodes, applying pressure betweensaid electrodes to soften and crowd the plastic insulation out of thatregion between electrodes and adjacent conductors and between adjacentconductors, and applying a welding current through said elements aftersaid heating and application of pressure results in a metal-to-metalcontact between adjacent conductors and adjacent electrodes.

6. ln the method for making electrical connections between conductors ofdifferent insulated bodies wherein said conductors are on plasticinsulating material, the steps comprising superirnposing `one of `suchbodies on a second body with the desired conductors to be connected insuperimposed relationship, applying heat and pressure simultaneouslybetween the insulating material which overlies said conductors to softenand crowd rthe insulating material away from such conductors, andthereafter passing a welding current through the superimposedconductors.

7. Apparatus for making electrical connections to an insulating bodyhaving conductors in rthe form of ribbons in said body, a pair ofelectrodes capable of applying pressure in a limited tarea to oppositesides of said body, heating means mounted on each of said electrodes forsoftening the insulation on said body when and as pressure is applied toand between said electrodes.

8. Apparatus as set fonth in claim 7 in which one of said electrodes hasan arcuate grooved portion at its end for snugly engaging a wire whichis to be connected to one of said conductors.

9. In a method for making electrical end connections to flexibleribbon-tape cables wherein conductors are embedded in a plasticmaterial, the steps comprising inserting each of said end connectionsinto one end of said cable in sandwiched relation between acorresponding one of said conductors and the plastic material overlyingthe same to crowd said overlying material away from the conductor andstress the same with the said material maintaining said end connectionsagainst its corresponding conductor, applying heat and pressure to theplastic material on correspondingly opposite sides of said conductor andsaid end connection by a pair of heated electrodes to soften and crowdthe plastic material out of that region between said electrodes and saidend connection and said conductor, and thereafter passing a weldingcurrent through `said electrodes to weld the end connection to -acorresponding conductor.

References Cited bythe Examiner UNITED STATES PATENTS 584,120 6/ 97Payne et al. 219-91 1,613,957 1/27 Madden 219-86 2,343,664 3/44 Heiseret a1. 29-15555 2,349,495 5/44 Gilliam et al. 219-78 2,977,672 4/61Telfer 219-58 2,982,938 5/61 K'lumpp 339-97 RICHARD M. WOGD, PrimaryExaminer. ANTHONY BARTIS, Examiner.

1. APPARATUS FOR MAKING ELECTRICAL CONNECTIONS TO FLEXIBLE RIBBON-TAPECABLES WHEREIN CONDUCTOR IN THE FORM OF RIBBONS ARE EMBEDDED IN APLASTIC MATERIAL, A PAIR OF POINTED ELECTRODES CAPABLE OF APPLYINGPRESSURE IN A LIMITED AREA TO OPPOSITE SIDES OF SAID TAPE CABLE, HEATINGMEANS MOUNTED ON EACH OF SAID ELECTRODES FOR SOFTENING